A thermal printer is known which melts the ink of a transfer ribbon with the heat generating element of a thermal head and transfers the ink on a sheet. The thermal printer conveys the transfer ribbon and the sheet at the same speed and presses, through the thermal head, the transfer ribbon to contact the sheet. In this state, by means of the thermal head, the thermal printer prints on the sheet via the transfer ribbon.
Thermal printers include a printer having a ribbon saving mode, in which the printer stops the conveyance of a transfer ribbon and merely conveys a sheet in a non-print area if the length of the non-print area in a conveyance direction is above a given value, wherein the length of the non-print area is contained in printing data. Further, the printer carries out lifting the thermal head for separating the transfer ribbon from the sheet by means of separating the thermal head from the side of the sheet. In this way, the consumption of the transfer ribbon in the non-print area is restricted in the ribbon saving mode.
Before conveying a sheet to the part of the non-print area, the printer carries out the lifting to make the thermal head return to the former printable position and restarts the conveyance of the transfer ribbon.
However, during a ribbon saving processing which includes lifting the thermal head and lowering the thermal head, a mechanical operation such as lowering the thermal head is needed. In order to guarantee a time for the operation, it is needed to make a given length of non-print area in printing data when carrying out a ribbon saving processing. The necessary length of non-print area increases in proportion to a printing speed (a sheet conveyance speed).
Thus, it may happen in the case of a set high printing speed that the ribbon saving processing is unachievable if the length of non-print area is smaller than a necessary value.